4 Y 2 Si 7 O 2: A New Oxynitride
with Low Thermal Conductivity
Search for new thermal barrier materials with high‐temperature stability is very difficult because there are intractable choices among thousands of possible candidates. The present paper shows that identifying and developing new low thermal conductivity materials can be accomplished by first‐principles calculations of equilibrium crystal structure and elasticity, and thereafter making theoretical prediction of minimum high‐temperature lattice thermal conductivity basing on David Clarke's method for insulating materials. We highlight a new oxynitride ceramic,
4 Y 2 Si 7 O 2, with a low theoretical minimum thermal conductivity of 1.12 W·m−1·K−1.
The theoretical result is further validated by experimental measurement of thermal conductivity of dense and bulk N 4 Y 2 Si 7 O 2.
The experimental thermal conductivity is 1.50 W·m−1·K−1 at 1300 K. Furthermore, thermal properties of N 4 Y 2 Si 7 O 2
are investigated for evaluating its potential performances.
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Document Type: Research Article
Publication date: October 1, 2012